


Scarlett Fever

by Canadian_BuckBeaver



Category: Undertail - Fandom
Genre: Alternate Timelines, Alternate Universe, Alternate Universe - Modern Setting, Boys Kissing, Dorks in Love, F/M, Genderbending, Kissing, M/M, Magic, Making Out, Minor Character(s), Multi, Multiple Pairings, Multiple Partners, Original Character(s), Pansexual Character, Protective Grillby (Undertale), Teleportation, Temper Tantrums, Underfell Papyrus (Undertale), Underswap Papyrus (Undertale), Underswap Sans (Undertale), Undertale Monsters on the Surface, Yaoi, sexy kisses
Language: English
Status: Completed
Published: 2019-02-13
Updated: 2019-02-13
Packaged: 2019-10-27 08:41:07
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,205
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17763506
Author URL: https://archiveofourown.org/users/Canadian_BuckBeaver/pseuds/Canadian_BuckBeaver
Summary: Sai's Mansion has seen many things.  It has seen the comings and goings of monsters of ever kind, it has seen the movings of humans, the birth of the human-monster hybrids.Can it survive the wrath of Scarlett, the female Fell Papyrus, when Yuri takes things a kiss too far?





	Scarlett Fever

**Author's Note:**

  * For [Saiyurimai](https://archiveofourown.org/users/Saiyurimai/gifts), [papao156](https://archiveofourown.org/users/papao156/gifts).



> OCs galore, based off many conversations and my other fanfic, Saicest

At first glance, it was a typical day at the mansion.  The sun was brightly shining, the solar panels and windmills glinting in the bright sunlight.  The soft breeze whispered through the flowers, leaves dancing on the edge of autumn.  It was a beautiful day, a perfect day for a walk.  Bucky, Lines, and Sai were walking amongst Asmodeus’ gardens, taking in the sight of his beautiful flowers and how his vegetable patch was coming along.

“It’s hard to believe that it has already been a year,” Lines said, examining a red rose.  Sai and Bucky had to agree.  Time had no meaning on this little island paradise.  As cliché as it was, it seemed like it was only yesterday that Lines and her Underfell Papyrus, Fell, had arrived at the mansion.  Yet, on the other hand, it seemed like they had been there forever.  In the best of ways of course.

Sai could still remember it. She had been in her room, dosing with her little twins, Bella still in her belly.  Sebastian had entered the room, the most peculiar look on the butler’s face.  “Do we have room for one more human and Underfell monster?” he had asked before handing the phone to Sai.  The judge was able to explain to Sai what he was asking of her.  A human had foolishly tried to pickpocket the skeleton and Fell wasn’t having any of it.  A quick slice of his bone sword and the human’s arm was on the ground, Fell’s wallet back in his pocket.  The judge, although sympathetic to the monster defending his property, could not let his “extreme” punishment go unscathed.  Fell would no longer be allowed to live amongst humans.

But an island that was a human-monster paradise…

“When the judge first described it I was worried that it would be some sort of reform school or boot camp,” Lines said, letting the flower go.  “And now it just feels like home.”

“Oh good, so the brainwashing is working,” Bucky said, sighing with fake relief.

Sai snorted and gave her a small smack to the arm.  “Bucky.  We’ve been over this.  Be nice to the prisoners and don’t tell them anything that might break procedure.”

“Sorry, boss,” Bucky said, saluting her with two fingers.

With a shake of her head, Sai was about to return back to the original conversation, when a loud commotion interrupted her.  “What in the everlasting hell…?” she asked, immediately walking towards the noise, Lines and Bucky at her heels.  She swore if her companions destroyed part of the mansion again she would make them rebuild it and then leash the lot of them.

There was a blur of blue and a flustered Berry caught up with them. He looked like he had been in the middle of some spring cleaning when he rushed out to see them. Pepper, his and Edge’s child giggled from her carrier on her back.  She saw her favourite aunties and they were all headed on an adventure!  This was way better than cleaning.  “What on Asgore’s earth was that?” he asked Sai, taking great care to keep pace with her.

She shook her head.  “I don’t know but we are about to find out,” she said, walking faster as the noises grew louder.  There was a small gathering of people where the shouting seemed to be originating from.  However, the tone and volume of said voice were slightly familiar. She could hear shouting, but the words were still incomprehensible.   “Is that Edge? Or Fell? I still can’t tell the two of them apart yet,” she asked, squinting at the gathering of people and monsters.

Lines shook her head as she hurried to the commotion.  “I think it’s Scarlett actually.” She whispered.

Biting back a groan, Sai hurried to try to separate the monsters, trying to disrupt the fight or argument.  In addition to her many companions and friends, the mansion was also home to the gender-bent versions of her friends and her.  They were fascinating, but just as able to stir up trouble just as much as the rest of them.  First, there was Yuri, the male version of Sai, was mated to a female version of Grillby and Gaster.  Bucky’s male version was named Bert, he too was mated to a female Stretch.  And then there was Leo, the male Lines, the one who was mated to Scarlett, a female version of Edge and Fell.

In Sai’s opinion, Scarlett was all Fell attitude, but also all the hormones of a PMS-ing female.  She threw frequent temper tantrums that had made the babies blush as they watched her.  Leo undoubtedly loved her to pieces, and Scarlett soaked up the attention like a wet sponge.  How he kept her in line was another question but….

Oh.

Sai’s eyes widened when he saw the commotion.  Scarlett was indeed the one throwing a hissy fit, being held back by a desperately pleading Bert.  Bert looked scared, blue eyes wide and fearful and sweat beading at his temples.  Scarlett, on the other hand, was a goddess of anger.  She was grinding her fangs and snarling whispered profanities.  If the day had been even cooler, Sai would have sworn that steam was rising from her ears.  She was staring at a lip-locked couple, the clear target of her wrath.

“Oh my,” Bucky was blushing, staring at the couple as well.  Sai turned from the she-demon, jaw dropping when she saw them.

Yuri had pulled Leo into a deep kiss, his hands around the other’s hips.  His hands squeezed and kneaded, pulling the other closer and encouraging him to participate. Their lips pressed together, again and again, tongues dancing together and eyes closed in bliss. Leo’s hands were on his cheeks, holding him close, slowly drawing out the kiss. Even with all the companions hooting and hollering, cheering them on, they still drew out the kiss.  Savouring the moment.

They were putting a show, the three girls realized at the same moment, backing up quickly as to not encourage Scarlett’s wrath further. If those two wanted to put on a yaoi show for Scarlett they were certainly going about it the wrong way.

A firey hand clasped Sai’s shoulder, pausing her.  Glancing up quickly, Sai smiled at Grillby.  Seemed like everyone who had been in the house had been drawn out due to the commotion.  The bartender was signing to Sai. Sai, reading his hands, nodded.  “Everything is fine.  Leo and Yuri are just making out in front of Scarlet.”

“Suddenly that explains why it sounded like a harpist was being murdered,” Stretch said, wrapping his arms around Bucky, kissing her hair.  His warm eye lights looked her over, scanning her.  “We weren’t sure what to expect when we heard a female screaming, so we all ran over as quickly as we could.”

Fell was obviously coming down from an adrenaline high as Lines comforted him.  She held his hand, squeezing it and whispering softly to him as the monster took deep breaths, trying to calm his shaking bones.  Sai and Bucky had wondered numerous times if the Fell monsters all suffered from some form of PTSD.  If that was the case, they sincerely hoped that this wouldn’t trigger an episode for him.

As they watched, Fell took a deep breath, holding it before letting it out all at once.  His bones stopped shaking, and his magic calmed. There we go.  He gave Lines’ hand one last squeeze.  “You’re not thinking of making out with any of these losers while they are at it?” he asked her, a teasing tone coming to his voice.

Lines giggled and shook her head.  “You’re more than enough for me, handsome.”

Sai smiled but turned back to the scene. As she watched, Yuri’s hands travelled over the swell of Leo’s hips and ass, squeezing the flesh before grinding softly against him.  Leo gasped, eyes flying open and the spell was broken.  He stepped back, his cheeks on fire, his eyes still dazed by the kiss.  Yuri, on the other hand, looked as cool as a cucumber.  Like the cat who had gotten the cream.  “Well?  How’s that?  You certainly have her attention now.” Yuri winked, gesturing to a still snarling Scarlett.

“That was way more than getting her attention… or pissing her off.” Leo whispered, still in a daze.

Yuri shrugged, his playboy grin stretching across his lips.  “Maybe it worked a little too well,” he admitted, gesturing to Bert to release her.  “But I have to say that I very much enjoyed our experiment, and I am sure that the others did too.” He told the other male with a wink.  “Especially your special lady friend.”

Bert carefully released Scarlett.  He was whispering something to her, probably telling her not to react in the way that Yuri was looking for. Telling her to remain calm.  “I don’t need your advice!” Scarlett spat, gently pushing Bert away.  Her arms folded, she pouted looking away.

“I daresay that she enjoyed our little show,” Yuri said, glancing back at Leo, trouble brewing behind his eyes.  “Want to do it again?”

This did not go over well with Scarlett.  The Fell monster stomped her foot before turning her heel and walking away.  Her cheeks were red enough to double as a flashlight Sai noted to some amusement.

“Oh no!  If you want to kiss someone, go kiss Sai!” Leo told him before chasing after Scarlett. “Scarlett, wait!”

There was a devious chuckle from Yuri as he smirked.  “Seems like I did my job too well.”

“Is that what we are going to label it?” Bert asked him, confusion on his face.  “Poor Leo…”

“He will have her eating out of his hand again in no time,” Yuri assured him. Bert didn’t respond except with a soft sigh, pinching his nasal bridge.  Yuri seemed to be assessing him before the smirk returned. 

“You want to make out?”

Bert jumped, staring at his dearest friend. “What? No! I mean… thank you but no…”

The other male puckered up his lips and was slowly approaching him.  “Come on Bertie…. Show me some love~”

“I said no!” Bert began to glance around the little area, just now realizing just how trapped he was by the others.  “Yuri, I swear on the stars above…”

“KISS ME BERTIE!”

With a yelp, Bert dodged Yuri and began to run.  “Yuri get away!”

This was the wrong move.  It was now a game to the other man.  “Come on Bertie.  You can’t escape me forever~”

“Stretch!  Stretch get me out of here!” Bert called out, dodging around a tree, still running.

Yuri chased after him with his arms outstretched.  “Come here Bertie!  No one can save you now!”

“Aren’t you going to do something?” Sai heard Bucky softly ask someone.

The female Stretch, Sugar to those who lived at the mansion, was laughing beside her.  Shaking her skull, Sugar looked down at her with dancing eyes.  “Oh heavens no.  This is much too delicious to intervene.  Besides, I have to admit that I have been wondering about it…”

Bert ran around another tree, Yuri hot on his heels when it happened.

Bert tripped over a rock and, giving a startled yelp, vanished into midair. Yuri skidded to a stop, glancing around.  By now they were all familiar with the teleportation tricks of the judge monsters.  It was rather rare for humans to be able to do monster magic tricks, but it was not unheard of.  They, like monsters, usually would reappear within a few seconds of disappearing, a few feet from where they vanished, nothing wrong. 

However, Bertie did not reappear.

Yuri gave a dejected sigh before shaking his head.  “You win this round, Bertie!  I’ll get you next time though~” he sang before turning back to the mansion.  Sai just shook her head.  Knowing herself, he was probably heading in to seek out his mates and work out his frustrations.

Bert was safe.

* * * * *

“Remember when I said that it’s hard to believe that it has been a year since I arrived?” Lines said.  The girls and their mates had resumed their little walk through the gardens, Bucky was in front of them as she led them to the lilac bush that the demon priest had grown just for her. Bucky and Sai nodded, smiling at her. “Well, it may have been a year since I arrived, but I still get surprised at whatever the day brings.”

“Oh trust me,” Bucky said, turning the corner of the mansion, “I’ve been here longer than you and you never get used to it…” she paused in her step, staring.

Sai sighed and shook her head.  If Scarlett and Leo were having makeup sex in the garden again, Asmodeus would have their heads.

Instead of the female Fell monster, however, they came across Sugar.  The Swap monster was pulling on a mortified looking Bertie, one who had gotten himself stuck between the walls of the mansion.

“Now I’ve seen it all,” Lines said as they walked past the couple, watching as Sugar pulled at him.

Sai shook her head.  “Not even close.” She told her friend.  “Not even close.”

Stars, she loved it here.


End file.
